Onetap1

Onetap1 t1_j8wozaa wrote

Because of convection mostly.

The fire mostly happens in the bed, the bottom and you add new fuel on top of the hot burning coals.

The heat radiated from the fire bed causes the new fuel to break down (pyrolysis) into flammable gases, vapours and solid particles.

However, hot air rises, so the air flow goes upwards, through the bed of the fire. The excess air and combustion products go upwards, through the as-yet unburnt fresh fuel, and it carries away some of the combustible gases, vapours & particles upwards, away from the fire bed. It doesn't get burned and that's the soot.

Look up downdraught gasifier stoves and secondary combustion.

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Onetap1 t1_j8hrv1m wrote

The post below was something I posted on a UK motoring forum 20 years ago, so I've just copied and pasted it.

https://www.honestjohn.co.uk/forum/post/index.htm?t=6781

I also mentioned car/truck windscreen washer bottles as a legionella risk, which was 8 years before the UK's HSE issued a warning about using screen wash to kill the bacteria.

https://www.bbc.co.uk/news/10293519

"The wet cooling towers are the problem, as stated by many others.

The heat removed by the cooling process is rejected at the condenser, where the refrigerant vapour is condensed into a liquid and it's latent heat of condensation is released.

In wet AC systems the condensers are cooled by water. The water is cooled at the cooling tower and recirculated. The cooling tower ponds tend to collect all the particles in the air, limescale, leaves, insects, etc, and are often at lukewarm temperatures, providing ideal conditions for the growth of many organisms. The water is intentionally sprayed into the air to cause some of it to evaporate, creating an aerosol of water droplets containing any organisms that have been cultivated in the water.

The legionella bacteria is present in water everywhere and will multiply if given favourable conditions.

The risk of infection is much greater for the elderly or infirm, so the disease has affected many hospitals, in the past. The risk wasn?t recognized until a group of elderly ex-servicemen, attending an American Legion Convention were felled by a hotel cooling tower in Philadelphia in 1976. The disease had existed prior to that, but had been regarded as yet another strain of pneumonia.

The (UK) HSE's Code of Practice on Legionnaires' disease, L8, states that a foreseeable risk exists in;

a) water systems incorporating a cooling tower;

b) water systems incorporating an evaporative condenser;

c) hot and cold water systems;

d) other systems containing water at which is likely to exceed 20 degC and which may release a spray or aerosol."

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Onetap1 t1_j8hqn3v wrote

The cooling towers weren't 'properly maintained' by modern standards because the hazard wasn't recognized.

Cooling towers mostly vanished from AC systems in subsequent decades because the maintenance & chemical water treatment regimes are now so onerous and expensive. Air cooled condensers are more usual now.

Similarly, spray humidifiers were replaced with steam humidifiers, etc..

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Onetap1 t1_j8et0de wrote

They don't live in mechanical ventilation. They live in tepid water which has nutrients. Anything with warm water is hazardous.

The first case, where it was identified, killed a lot of US Legionnaires (armed forces veterans) at a convention at a hotel in Philadelphia. The source was an evaporative cooling tower, which uses evaporating water to discard waste heat from the air conditioning systems.

The thing about cooling towers is that the water is recycled from a pond in the base of the tower. It collects insects, dust leaves, limescale, etc, nutrients for bacteria. And the water is warm. The bacteria was distributed on the water droplets leaving the tower.

https://en.wikipedia.org/wiki/Legionnaires%27_disease#Epidemiology

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Onetap1 t1_j5vmipf wrote

He lost 2 sons in WW2, one was an RAF bomber pilot killed on the second day of the war, one killed in 1945 during the Granville Raid.

I've no idea what the thing with the boy on the boat was about.

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Onetap1 t1_iyr0mwj wrote

>Glad to see you admit

I seem to have missed that bit.

Shrinkable clay sub-soil may be the phrase you're struggling to recall, Mr foundation repair professional. It's probably not the problem. You should look up the word 'Professional' in a dictionary; it doesn't mean what you seem to think in this context.

Bye.

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Onetap1 t1_iyomj6c wrote

> Clay based soils shrink and swell

Which would cause subsidence cracking in a wall, due to unequal movement; under pin & make good etc..

it's not a wall; think on.

>What are your credentials to support your ill founded opinion?

I retired from the free advice business and will offer no further opinions. I'm sure you'll get there eventually.

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Onetap1 t1_iynofbs wrote

The weight of the gate (more relevant, the bending moment exerted by the gate) is overturning the column.

Maybe fix a wheel to the end of the gate and install a quadrant track for it to run on. No more weight that's overturning the column, the weight is supported by the wheel.

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Onetap1 t1_iyccghc wrote

>65% of HMS Trincomalee and over 95% of HMS Unicorn

I didn't know of those ships, thanks for that.

Tricomalee was built of Indian teak, which is probably why she's survived; I think ship worm would devour European wood in a few years. Unicorn has never sailed.

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